There are several factors that lend themselves to the prevalence of foundation problems in Matthews. We’ll explain these underlying issues below and offer some insight into how each adversely affects the concrete under your home.
Expansive soil is one of the leading causes of foundation problems in the United States. Matthews is located in the Piedmont Plateau region, which is underlain by clay loam. The clay-rich dirt in the area creates a variety of problems for home foundations, depending on the weather.
During rainfall, clay soil readily soaks up runoff. As it absorbs water, it expands in volume and puts undue pressure on your concrete walls and slab. This hydrostatic pressure can lead to inward bowing and eventual cracking of your slab and basement walls as the stress becomes too intense. Expanding soil commonly leads to a loss of your foundation’s structural integrity that can cause foundation failure if left unrepaired.
The clay dirt in Matthews is referred to as shrink-swell soil because it also loses volume when it dries. During periods of little or no rain, the moisture content in your soil is depleted, and the earth around your home shrinks. Typical soil shrinks very little and often uniformly enough as not to cause damage.
However, the clay in the ground tends to dry unevenly because of how absorbent it, leaving portions of your foundation with varying support underneath. Under the immense weight of your home, concrete that is unbraced will sink more rapidly into the earth. This hazardous differential settling is a primary cause of structural damage in Matthews.
Lastly, clay soil’s ability to absorb and retain water means that it suspends moisture from runoff against your foundation for long periods. Your concrete can remain exposed to water for days or weeks at a time, depending on the rainfall.
The longer water interacts with your foundation, the more likely it is to soak or leak through pores or cracks into your home. As such, water intrusion and under-home moisture build-up are widespread problems in the area.
Many North Carolina homes are built on multi-level foundations, typically in the form of partial basements. These foundations are convenient and more affordable than full basements and crawlspaces. However, they leave your home sitting on soil at different depths, which can predispose your house to differential settling.
Clay soil dries at varying rates, and the drainage depends largely on the depth of the soil. As runoff soaks deeper into the earth, the shallow dirt dries more quickly than soil located at greater depths.
Therefore, multi-level foundations rely on earth with disparate moisture content that can expand and shrink at different rates, leading to uneven support and the potential for structural damage.
The problems with expansive soil are made worse by the climate in Matthews. The city experiences an average of around 45 inches of rainfall each year, nearly 50% higher than the national average. The rain is heaviest from June to October, when tropical storms and hurricanes are prevalent in the area.
The above average and concentrated rainfall soak the soil more readily, causing it to expand and put excess pressure on your concrete foundation. The runoff during and following precipitation will also be suspended by the clay in the ground for long periods, increasing the likelihood of flooding, water intrusion, and moisture wicking into your home.
High, Year-Round Humidity
Lastly, Matthews experiences a relatively high humidity level throughout the entire year, averaging between 60 and 70%. Humid air can be detrimental in any portion of your home, but crawlspaces and basements are particularly prone to moisture issues.
The moist air outside naturally makes its way into your under-home area and gets trapped there. As the moisture builds, it can damage building material, lead to mold growth, and create problems if it seeps into your living space.